DKMS install fails on 5.4 kernel

[rogerjames99]

Changes to the kernel build process have broken installation on Linux 5.4+ kernels.

DKMS make.log for spi-ch341-usb-1.0.0 for kernel 5.4.0-42-generic (x86_64)
Fri 31 Jul 08:56:46 BST 2020
make[1]: Entering directory '/usr/src/linux-headers-5.4.0-42-generic'
DESCEND objtool
/usr/src/linux-headers-5.4.0-42-generic/tools/build/Makefile.build:37: /usr/src/linux-headers-5.4.0-42-generic/tools/build/Build.include: No such file or directory
make[5]: *** No rule to make target '/usr/src/linux-headers-5.4.0-42-generic/tools/build/Build.include'. Stop.
make[4]: *** [Makefile:43: /usr/src/linux-headers-5.4.0-42-generic/tools/objtool/fixdep-in.o] Error 2
make[3]: *** [/usr/src/linux-headers-5.4.0-42-generic/tools/build/Makefile.include:5: fixdep] Error 2
make[2]: *** [Makefile:67: objtool] Error 2
make[1]: *** [Makefile:1835: tools/objtool] Error 2
make[1]: *** Waiting for unfinished jobs....
make[1]: Leaving directory '/usr/src/linux-headers-5.4.0-42-generic'

[rogerjames99]

I fixed this by changing SUBDIRS= to M= in dkms.conf.
I will generate a pull request for this